Pneumatic single-lumen medical gas conserver

Abstract

A pneumatic single-lumen medical gas conserver combines the advantages of typical single-lumen and dual-lumen conservers. In particular, a pneumatic single-lumen conserver can provide a rapid response to patient inhalations without the need for a more expensive dual-lumen cannula hose. In addition, after delivering oxygen the conserver has a specific pneumatically-implemented delay period before being able to detect the next inhalation to inhibit “double pulse” deliveries. In addition to a conserving or pulse flow mode, the conserver can provide a user-selectable gas flow at a continuous or constant flow mode.

The invention claimed is: 
     
       1. A method of manufacturing a pneumatic medical gas conserver for providing a volume of medical gas to a patient, comprising
 forming a supply port for receiving a regulated flow of a medical gas; 
 forming a patient port for providing a flow of medical gas to a patient through a single-lumen cannula; 
 assembling a sensing valve in gaseous communication with the patient port for detecting an inhalation by the patient to trigger delivery of the medical gas to the patient port; and assembling a check valve gaseously disposed between the sensing valve and the patient port for decoupling the sensing valve from the patient port in response to detection of the inhalation by the sensing valve. 
 
     
     
       2. The method of  claim 1  further comprising coupling a gas regulator in communication with the supply port. 
     
     
       3. A method of using a pneumatic medical gas conserver for providing a volume of medical gas to a patient, comprising:
 receiving a regulated flow of a medical gas at a supply port; providing a flow of medical gas to a patient at a patient port through a single-lumen cannula; 
 at a sensing valve in gaseous communication with the patient port, detecting an inhalation by the patient to trigger delivery of the medical gas to the patient port; and 
 at a check valve gaseously disposed between the sensing valve and the patient port, decoupling the sensing valve from the patient port in response to the detection of the inhalation by the sensing valve. 
 
     
     
       4. The method of  claim 3  wherein decoupling comprises decoupling the sensing valve from the patient port before the medical gas is delivered to the patient port. 
     
     
       5. The method of  claim 3  wherein decoupling comprises gaseously isolating the sensing valve from the delivered medical gas. 
     
     
       6. The method of  claim 3  further comprising coupling a gas regulator in gas communication with the supply port.